1. Field of the Invention
The present invention relates to an integrated circuit (IC) and a method for automatically tuning process and temperature variations.
2. Description of the Related Art
In general, a process variation occurring in the manufacture of an IC must be tuned to accurately operate the IC. A conventional method of tuning a process variation will be described in brief with reference to FIG. 1.
FIG. 1 is a circuit diagram illustrating a conventional method of tuning a process variation. A case where circuit elements of which process variations are to be tuned for low pass filters (LPFs) 12 will be described with reference to FIG. 1. To tune the process variations of the LPFs 12 in a conventional IC 10, a test signal is input to an input node 11 when power is applied to the conventional IC 10 to perform an initialization, passes through the LPFs 12, and is output to a final rode 13. The test signal is transmitted to a process variation tuning circuit (not shown) installed outside through a modem (not shown). A tuning control signal is input from a tuning circuit installed outside to an input node 14 so as to tune the process variations of the LPFs 12. The above-described conventional method is achieved using a signal output from the final node 13 of the conventional IC 10. Thus, process variations occurring in circuit elements constituting the LPFs 12 are not directly considered.
The signal output from the final node 13 is transmitted to the tuning circuit installed outside, and a control signal is received from an external source with respect to a process variation. Thus, a relatively long time is required for tuning a process variation in the conventional method.
In addition, a modem or the like must be installed to communicate with an external tuning circuit. Thus, an IC has a complicated structure.
Only when the power is applied to the IC to perform the initialization, the tuning circuit operates to tune the process variation. Thus, temperature variations of the circuit elements occurring due to heat during the operation of the IC cannot be considered.